When I came home last night, I thought my previously healthy Windows 7 machine was dead. It was making a horrendous squeal and refused to reboot multiple times. Turns out it was asleep.

I'm not sure what kind of sleep it was in (I was only gone for 6 hours and I've left it alone for half a day before and it was fine), but a regular reboot refused to restart it. So I did that ten times in a row, before giving up. I had to pull out the power cable (it's a desktop) and let the motherboard's lights go off and battery drain out. After this, it was able to correctly boot up again to a "Resuming Windows" screen, which then didn't respond to any keyboard/mouse inputs, so I had to reset again.

It's not like previous the sleep mode in Windows versions worked perfectly, but the manufacturer usually tests it once or twice to make sure that it's compatible enough that you don't have to jump through crazy hoops to re-enable your system. So our hint is to disable sleep/hibernate/power save mode on your system, in case it's incompatible, for now to save yourself headaches later.